using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var lm = new LevelManager

        {

            version = 1.0f,

            health = 100,

        };

        lm.powers = new Dictionary<string,int>();

        lm.powers.Add("Hadoken",15);

        lm.powers.Add("Electricity",20);

        lm.powers.Add("Rocket",25);

        lm.powers.Add("Kick",20);

        var json = Newtonsoft.Json.JsonConvert.SerializeObject(lm, Newtonsoft.Json.Formatting.Indented);

        Console.WriteLine(json);

    }

}

​

public class LevelManager

{    

    public float version  { get; set; }

    public int health  { get; set; }

    public Dictionary<string,int> powers  { get; set; }

}

​